1. Field of the Invention
This invention relates to the field of fruit processing methods and apparatus and, in particular, to methods and apparatus for scooping the meat from citrus fruit and sectioning the extracted fruit meat.
2. Description of the Prior Art
Citrus fruits are generally comprised of an outer colored peel (flavedo), an inner white spongy peel (albedo) and a central meat formed in wedge shaped segments, that are collectively surrounded by a fibrous membrane network, commonly referred to as "rag". Within the meat is a core, comprised of essentially the same pectin substance comprising the albedo, which extends axially from the stem end to the blossom end of the fruit. In most varieties the core is surrounded by seeds within the adjacent meat. The individual meat segments primarily comprise juice sacks, which are elongated, oval elements that contain fruit juice and are held together by an epicuticular wax. Insofar as human consumption is concerned, the juice sacks are considered the most valuable portion of the fruit, the other components--the peel, rag, core and seeds--primarily having other uses in production of cattle feed, essential oils and the like.
The prior art has devised various methods and apparatus by which the fruit meat can be extracted.
In the system described in U.S. Pat. No. 3,700,017, an axially-oriented fruit is placed between two spikes that are sharply driven, respectively, into the stem and blossom ends of the peel. The spikes and attached fruit are then rotated while two knives move laterally across the rotating fruit to cut the peel from the meat. Although such a system does effectively extract the meat from the fruit, it does not eliminate the core, and cutting the peel in this fashion releases bitter peel oils and other undesirable flavor components found in the peel, which contaminate the meat. Furthermore, in order to allow the spike to be inserted into the fruit's stem and blossom ends, where the core lies beneath the peel, fairly precise orientation of the fruit is critical for the successfully peeling the fruit.
Other systems have evolved various types of chemical baths, which dissolve the various fruit membranes, as shown in U.S. Pat. Nos. 4,560,572 and 4,139,651. And still further systems enzymatically detach the meat from the albedo by infiltration of pectinase into the albedo, beneath the flavedo, such as shown by U.S. Pat. Nos. 5,000,967; 5,170,698; 5,196,222; 5,231,921; and 5,200,217. However, such systems have a limited volume throughput, because of the processing time required to obtain enzymatic breakdown of the pectinase comprising the albedo layer of the peel, and such processes entail additional costs associated with the necessary enzymes and the related heating, cooling and other processing apparatus.
Still another extraction method uses high pressure fluid jets, as shown by U.S. Pat. Nos. 1,982,741; 4,294,861; and 4,300,448, in which the fruit is oriented and cut in half, and the exposed meat is placed in front of a fluid jet nozzle. High pressure fluid emitted from the nozzle blasts the fruit meat from the peel. These systems have limited commercial practicality because of the large volume of pressurized fluid required to obtain commercially acceptable yields. Furthermore, they are limited by the criticality of the orientation of the fruit and by the fact that sectional membranes tend to fold over and impede the fluid jet's ability to remove the meat most deeply seated within the peel.
Yet another system is shown by U.S. Pat. No. 4,885,182, which feeds the fruit into a dual conveyor and extraction apparatus that includes a plurality of action cups for holding the fruit. After the fruit is cut in half, the halves are indexed through successive meat extraction and removal stations. The extraction station includes an extraction element that separates a hemispherical section of meat from the peel. The removal station includes a removing element that gently removes any fruit meat remaining within the peel after the bulk of the meat has already been removed. The extraction station includes a rotating, ladle-shaped extraction element having a cutting bowl. While rotating, the cutting bowl is rotated 90 degrees such that its sharp peripheral edge severs the hemispherical chunk of meat from the peel, similarly to a spoon scooping ice cream from a carton. In theory, the severed meat chunk tumbles from the peel and is collected for subsequent processing. But in any event, the core adheres to the hemispherical chunk.
Among the many obvious problems with the latter prior art apparatus is the fact that the edge of the cutting bowl (i.e., the "spoon") quickly dulls, and when dull, it is substantially ineffective in extracting the meat from the peel. Secondly, even if and when cleanly cutting the meat from the peel, the apparatus has no means by which the extracted meat half can be sectioned. The extracted halves are removed from the peel as hemispherical chunks, by a means which is not clearly shown. Thirdly, as the fruit size changes, the size of the entire cutting bowl and the extraction station must also be changed. The cost of manufacturing the cutting bowls in different sizes is high, and severely limits the economic practicality of the device. Certainly, in a juicing operation (for which that apparatus was apparently invented), these disadvantages might be tolerated. However, they render the apparatus ineffective for rapidly producing cleanly sectioned and cut fruit on a long-term, cost-effective basis.
Therefore, what is needed is some type of apparatus which can economically and practically provide cleanly removed and cut fruit meat in commercial volumes, and can operate efficiently on varying sizes of fruit.